/*
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 */

package org.dom4j.io;

import java.io.IOException;

import org.dom4j.Document;

import org.xml.sax.ContentHandler;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

/**
 * <p> <code>SAXValidator</code> validates an XML document by writing the
 * document to a text buffer and parsing it with a validating SAX parser. This
 * could be implemented much more efficiently by validating against the dom4j
 * object model directly but at least allows the reuse of existing SAX based
 * validating parsers. </p>
 * 
 * @author <a href="mailto:james.strachan@metastuff.com">James Strachan </a>
 * @version $Revision: 1.2 $
 */
public class SAXValidator
{
   /** <code>XMLReader</code> used to parse the SAX events */
   private XMLReader xmlReader;

   /** ErrorHandler class to use */
   private ErrorHandler errorHandler;

   public SAXValidator()
   {
   }

   public SAXValidator(XMLReader xmlReader)
   {
      this.xmlReader = xmlReader;
   }

   /**
    * Validates the given <code>Document</code> by writing it to a validating
    * SAX Parser.
    * 
    * @param document is the Document to validate
    * 
    * @throws SAXException if a validation error occurs
    * @throws RuntimeException DOCUMENT ME!
    */
   public void validate(Document document) throws SAXException
   {
      if(document != null)
      {
         XMLReader reader = getXMLReader();

         if(errorHandler != null)
         {
            reader.setErrorHandler(errorHandler);
         }

         try
         {
            reader.parse(new DocumentInputSource(document));
         }
         catch(IOException e)
         {
            throw new RuntimeException("Caught and exception that should "
               + "never happen: " + e);
         }
      }
   }

   // Properties
   // -------------------------------------------------------------------------

   /**
    * DOCUMENT ME!
    * 
    * @return the <code>XMLReader</code> used to parse SAX events
    * 
    * @throws SAXException DOCUMENT ME!
    */
   public XMLReader getXMLReader() throws SAXException
   {
      if(xmlReader == null)
      {
         xmlReader = createXMLReader();
         configureReader();
      }

      return xmlReader;
   }

   /**
    * Sets the <code>XMLReader</code> used to parse SAX events
    * 
    * @param reader is the <code>XMLReader</code> to parse SAX events
    * 
    * @throws SAXException DOCUMENT ME!
    */
   public void setXMLReader(XMLReader reader) throws SAXException
   {
      this.xmlReader = reader;
      configureReader();
   }

   /**
    * DOCUMENT ME!
    * 
    * @return the <code>ErrorHandler</code> used by SAX
    */
   public ErrorHandler getErrorHandler()
   {
      return errorHandler;
   }

   /**
    * Sets the <code>ErrorHandler</code> used by the SAX
    * <code>XMLReader</code>.
    * 
    * @param errorHandler is the <code>ErrorHandler</code> used by SAX
    */
   public void setErrorHandler(ErrorHandler errorHandler)
   {
      this.errorHandler = errorHandler;
   }

   // Implementation methods
   // -------------------------------------------------------------------------

   /**
    * Factory Method to allow alternate methods of creating and configuring
    * XMLReader objects
    * 
    * @return DOCUMENT ME!
    * 
    * @throws SAXException DOCUMENT ME!
    */
   protected XMLReader createXMLReader() throws SAXException
   {
      return SAXHelper.createXMLReader(true);
   }

   /**
    * Configures the XMLReader before use
    * 
    * @throws SAXException DOCUMENT ME!
    */
   protected void configureReader() throws SAXException
   {
      ContentHandler handler = xmlReader.getContentHandler();

      if(handler == null)
      {
         xmlReader.setContentHandler(new DefaultHandler());
      }

      // configure validation support
      xmlReader.setFeature("http://xml.org/sax/features/validation", true);

      // configure namespace support
      xmlReader.setFeature("http://xml.org/sax/features/namespaces", true);
      xmlReader.setFeature("http://xml.org/sax/features/namespace-prefixes",
         false);
   }
}

/*
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided that the
 * following conditions are met:
 * 
 * 1. Redistributions of source code must retain copyright statements and
 * notices. Redistributions must also contain a copy of this document.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * 3. The name "DOM4J" must not be used to endorse or promote products derived
 * from this Software without prior written permission of MetaStuff, Ltd. For
 * written permission, please contact dom4j-info@metastuff.com.
 * 
 * 4. Products derived from this Software may not be called "DOM4J" nor may
 * "DOM4J" appear in their names without prior written permission of MetaStuff,
 * Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
 * 
 * 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
 * 
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
 */
